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Silverfish

This article was published originally on 4/10/1998

Byline:

by Donald Lewis, Department of Entomology

The moderately-common and well-known silverfish are a wingless, flat insects with two long, slender antennae on the front and three long, slender "bristles" at the rear of a tapered, carrot-shaped body. They are PI inch long when fully grown. The body is covered with shiny silver scales.

Silverfish may be found almost anywhere in the house, but are most common in moist, warm locations (such as laundry rooms and bathrooms around sinks, showers and other plumbing fixtures). They are frequently trapped in the bottom of sinks or bathtubs because they fall in seeking moisture and then cannot climb out. Silverfish are most active at night and run very swiftly with a wiggling motion that resembles the swimming action of a fish.

Silverfish are pests primarily because their presence is a nuisance and an annoyance. Damage to foods, fabric, paper, books, or wallpaper is possible but unlikely in most situations. Significant damage is likely only in cases of very large infestations present over long periods of time.

In other words, control of an occasional silverfish may not be necessary, especially if infestations are limited to small areas. The fist step in control is to eliminate moisture problems where the pests develop (fix plumbing leaks, caulk cracks and gaps, use a fan or a dehumidifier, etc.). Household residual insecticides applied as sprays, dusts, or baits can be used if conditions warrant. Treat cracks, crevices, wall voids and other likely hiding spots in the areas where the pests are noticed.